Introduction & background

What is open source?

  • Software source code is the recipe for a piece of software; the human-readable code that is usually compiled into machine code before the software is distributed
  • Without the source code, it isn’t possible 1 to inspect what the software does, or make modifications to it
  • Broadly, software can be proprietary (closed source) or open source. With closed-source software (which in the past was the vast majority of software in use) the source code is kept a trade secret by the software developer. Common examples of closed-source software is Microsoft Windows and Office, Apple macOS2 and Adobe Photoshop.
  • You may see the term “free software” used in place of open source3 - in this context this does not refer to the software not costing any money; think “free as in freedom”
A small snippet of source code from revealjs, the presentation framework powering this slide deck.

A very brief history of Open Source

  • Much of the early days of computing took place at universities, where sharing code with colleagues was part of the culture. However, as computing (including business and home computing) became increasingly commercial in the 1960s and 1970s, code started to be copyrighted and/or protected as trade secrets, with vendors charging for licenses.
  • The modern open-source movement has its roots in the 1980s when Richard Stallman at the Massachusets Institute of Technology (MIT) in the USA founded the GNU project, which aimed to replace the major components of the then-dominant Unix operating system with open-source components, and the Free Software Foundation (FSF). This is when open-source (“copyleft”) licensing was conceived; a way of releasing software code in such a way that anyone who makes modifications of open code is cannot legally make their version closed-source.4
Ken Thompson and Dennis Ritchie working on early UNIX in 1971. Source: The Computer History Museum.
The original posting of the GNU Manifesto. Source: the Free Software Foundation.

A very brief history of Open Source

  • This was followed in the early 1990s by Linus Torvalds using these tools to create the Linux project which subsequently turned into a hugely popular open operating system.
  • The git project, originally created in 2005, was a huge improvement to collaborative development which improved the ability of geographically dispersed contributors to work on large open source projects together, and forms the basis of Github.
  • Subsequent large open source projects sprung up that ended up being foundational software - Docker, Python, Apache and PostgreSQL among many others.
Tux, the Linux mascot.
Git and Github.

Open source today

Open source rules the world! Open-source/free software is everywhere.

  • The Linux operating source kernel combined with the Apache or Nginx server software runs on the majority of servers, so it effectively runs the internet.
  • The Android smartphone OS has many open source components.
  • Even Microsoft, historically a symbol of proprietary software, now releases many tools (e.g. VS Code) as open source.
Major open source projects. Click for a larger version. Source: IDC

Benefits of open source

According to NHS England

The benefits of Open Source [to NHS trusts] are:

Ownership: Due to the vast configurability of open source software, Trusts have more control over the system. These modifications allow the technology to be completely bespoke to the Trust’s needs.

Accessibility: Open source software can be used and changed by anyone. This accessibility allows for constant developments and improvements made to the software.

Freedom: The supplier and maintenance needed to maintain the software are selected entirely by the Trust, with no lock in or long term commitments should situations change

Cost-effective: The licensing of open source software is significantly reduced compared to its proprietary counterpart.

Empowering: From clinicians to nurses, healthcare professionals have more input on software improvements and uses. This is bridging the gap between staff and technology, which will be critical for matters like the Paperless 2020 initiative.

Best Practice: Much like in the practice of medicine, open source runs on the philosophy of universally shared knowledge. New ideas and solutions are combined and promoted for the community’s benefit.

Source: https://www.england.nhs.uk/digitaltechnology/open-source/

Common misconceptions

Myth 1

“Open source software is less secure”

With all else being equal, open source code with many people (including, for example, paid security researchers) being able to review an application’s source code tends to make it more secure, not less.

Myth 2

“Open source is amateur or low-quality software”

Much of the internet runs on open-source software (e.g. Linux, Apache, PostgreSQL); many are maintained by top-tier engineers at Google, Meta, and others. Open-source tools are also becoming more commonplace in mission-critical systems e.g. hospital systems, banks and government.

Myth 3

“If we use open-source tools, we’ll have to release our work as open source as well”

The common open source licenses say nothing about needing to release the code for products that use open source libraries or software; we only have to give attribution. Only if we modify the code (for example, in the event we wanted to build a custom SCW version of a library or application) does the “copyleft” requirement apply.

Myth 4

“If we rely on open-source tools, we’d be snookered if they suddenly decided to close the source and start charging money”

The major open licenses are all irrevocable. Once a version of a tool or library has been released under an open license, that tool or library is open source in perpetuity. It’s always possible that (especially corporate-backed) projects could go closed-source for future versions, but in that case it is very likely that someone will take the last open version and “fork” it off into a separate project - this has happened many times e.g. LibreOffice from OpenOffice, MariaDB from MySQL.

Myth 5

“If we use an open-source tool on sensitive/proprietary data (e.g. SUS) we are at risk of this leaking out, or we are required to release it along with our code”

The open source licenses apply to the code itself, not the data we use it on. Even if we did decide to release one of our own products as open source, there is no requirement at all to publish any data alongside it. Furthermore, the fact that we can inspect the source code means we can assure ourselves as to how safe a tool is ourselves; with closed-source tools we have to trust the developer’s word for it (or, at best, an external security audit). Open tools such as R, python and PostgreSQL are in widespread use even with highly sensitive data (banks, governments, healthcare).

Open source in the UK public sector - examples

gov.uk

Widely recognised as one of the better government service portals, the gov.uk frontend is fully open source and hosted on GitHub by the Government Digital Service5.

The gov.uk frontpage.

New Hospital Programme demand and capacity model

Released by the Strategy Unit (part of Mids & Lancs CSU) earlier in 2025 as part of the New Hospital Programme, this Python-based 6 platform is designed to model future demand on hospital services using a complex and evolving set of inputs, parameters and outputs.

A snippet from the New Hospital Programme model explainer page7.

OpenEyes

OpenEyes is an Electronic Patient Record (EPR) specifically designed for the ophthalmic specialty8 that is developed and released on Github under the AGPL open source license. It was developed in response to existing commercial EPRs being a poor fit. It has seen widespread success with universal deployment across Wales and Scotland and increasing rollout in England as well as international deployments.

A screenshot of the Openeyes EPR.

Various examples from the NHS

Closing thoughts

A major benefit of the open-source model is that whilst every new hospital will have to be built brick by brick, nobody using a model to plan a hospital will ever have to start from scratch. Because it is open source, the NHP model can be developed, iterated and improved upon for many years to come.

Building on the example set by this model, openness should become standard practice for all NHS analytical tools. Sharing code transparently not only builds trust and ensures quality but also sets a benchmark for how such tools can deliver maximum public value.

- Chris Beeley, Head of Data Science, The Strategy Unit 9

Resources

Background reading

Open source in the NHS and UK Government

Thank You!


Contact:

Code & Slides:


Footnotes

  1. at least not easily possible

  2. with exception of some kernel components

  3. there are technically differences, but the terms are often used interchangeably

  4. a number of different open-source licenses exist today e.g. GPL, MIT and the BSD license. They all have slightly different legal terms and conditions.

  5. https://github.com/alphagov/govuk-frontend

  6. https://www.strategyunitwm.nhs.uk/news/transforming-hospital-planning-open-source-demand-and-capacity-model

  7. https://connect.strategyunitwm.nhs.uk/nhp_model_explainer/

  8. https://openeyes.apperta.org/

  9. https://www.strategyunitwm.nhs.uk/news/transforming-hospital-planning-open-source-demand-and-capacity-model